Funding for this research was provided by:
National Natural Science Foundation of China (61673141)
National Natural Science Foundation of China (61571168)
Alexander von Humboldt Foundation of Germany
Fok Ying Tung Education Foundation of China (151004)
Article History
Received: 19 February 2019
Revised: 24 June 2019
Accepted: 24 June 2019
First Online: 12 July 2019
Compliance with Ethical Standards
:
: The authors claim that there are no potential conflicts of interest. In addition, this submission has been approved by all co-authors.